$\gamma$-ray spectra from the radiative capture of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ particles by tritons have been obtained over the energy range $0.5\le E\left({}_{}{}^3{}_{}{}^{}\mathrm{He}\right)\le 11.0$ MeV. Strong transitions were seen to the ground and first two excited states of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$; excitation curves and angular distributions are presented. The integrated cross section for the inverse reaction ${}_{}{}^6{}_{}{}^{}\mathrm{Li}({\gamma }_0, t){}_{}{}^3{}_{}{}^{}\mathrm{He}$ up to $E_{\gamma }=25\mathrm{}$ MeV is found to be 9.3±1.4 MeV mb. Evidence is also found for a transition to the second $T=1\mathrm{}$ state of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$. The results are discussed in the framework of the direct-capture model. Substantial T+${}_{}{}^3{}_{}{}^{}\mathrm{He}$ clustering is evident in the four observed ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ final states.

• Received 29 July 1968

DOI:https://doi.org/10.1103/PhysRev.176.1147